Expression profiles of metallothionein-I/II and megalin/LRP-2 in uterine cervical squamous lesions.

Metallothioneins (MTs) are phylogenetically old cysteine-rich proteins, which are implicated in a variety of physiological and pathological processes. Their growth-regulating, anti-apoptotic and anti-inflammatory functions have been attributed not only to intracellular free radical scavenging and to zinc and copper regulation but also to the ability of secreted MT to bind on surface lipoprotein receptor-megalin/LRP2, which enables the endocytosis of MT-I/II and a wide range of other functionally distinct ligands. In the present study, we analysed the expression pattern of both proteins in 55 cases of premalignant transformation of cervical squamous cells, i.e. in low- and high-grade squamous intraepithelial lesion (LSIL and HSIL). The data showed that in LSIL (cervical intraepithelial neoplasia CIN1; N = 25) MTs were present only in basal and parabasal cells and that megalin was only weakly expressed. In HSIL (CIN2; N = 15 and CIN 3/carcinoma in situ; N = 15), however, overexpression and co-localization of MT with megalin were found in the entire hyperplastic epithelium. Moreover, megalin immunoreactivity appeared on the glandular epithelium and vascular endothelium, as well as on lymphatic cells in stroma. Besides, multiple megalin-positive cells expressed phosphorylated Akt1, implying that MT- and/or megalin-dependent prosurvival signal transduction pathways might contribute to the development of severe cervical dysplasia. The data emphasize the diagnostic power of combined MT/megalin analysis in pre-cancer screening.

Expression Profiles of Metallothionein I/II and Megalin in Cuprizone Model of De- and Remyelination.

Copper chelator cuprizone (CPZ) is neurotoxicant, which selectively disrupts oligodendroglial respiratory chain, leading to oxidative stress and subsequent apoptosis. Demyelination is, however, followed by spontaneous remyelination owing to the activation of intrinsic CNS repair mechanisms. To explore the participation of metallothioneins (MTs) in these processes, in this study we analyzed the expression profiles of MT-I/II and their receptor megalin (low-density lipoprotein receptor related protein-2) in the brain of mice subjected to different protocols of CPZ feeding. Experiments were performed in female C57BL/6 mice fed with 0.25% CPZ during 1, 3 and 5 weeks. They were sacrificed immediately after feeding with CPZ or 2 weeks after the withdrawal of CPZ. The data showed that CPZ-induced demyelination was followed by high astrogliosis and enhanced expression of MTs and megalin in white (corpus callosum and internal capsule) and gray matter of the brain (cortex, hippocampus, and cerebellum). Moreover, in numerous cortical neurons and progenitor cells the signs of MT/megalin interactions and Akt1 phosphorylation was found supporting the hypothesis that MTs secreted from the astrocytes might directly affect the neuronal differentiation and survival. Furthermore, in mice treated with CPZ for 5 weeks the prominent MTs and megalin immunoreactivities were found on several neural stem cells and oligodendrocyte progenitors in subgranular zone of dentate gyrus and subventricular zone of lateral ventricles pointing to high modulatory effect of MTs on adult neuro- and oligodendrogenesis. The data show that MT I/II perform important cytoprotective and growth-regulating functions in remyelinating processes activated after toxic demyelinating insults.

Osteopontin-metallothionein I/II interactions in experimental autoimmune encephalomyelitis.

Osteopontin (OPN), an extracellular matrix (ECM) glyco-phosphoprotein, plays an important role in autoimmune-mediated demyelinating diseases, including multiple sclerosis and experimental autoimmune encephalomyelitis (EAE). As an integrin and CD44 binding protein it participates in bidirectional communication between the ECM and target cells and affects transduction pathways that maintain neuronal and immune cell homeostasis. Its biological activity is also heavily influenced by microenvironment, which stimulates the cleavage of OPN and changes its functions. In this study we estimated the expression profile of OPN in neural tissues of DA rats during the first relapse of chronic relapsing EAE and investigated the relationship of OPN to metallothionein I+II (MTs), which play pivotal role in zinc-related cell homeostasis and in protection of CNS against cytokine-induced injury. The data showed that in EAE rats OPN mRNA and protein levels increased concurrently with the transcription of MTs and that within the spinal cord (SC) lysates EAE-afflicted rats had a higher content of OPN fragments of low molecular weight than untreated and CFA-treated rats. The expression of OPN and MTs was upregulated on ependymal, lymphoid and astroglial cells and on multiple αvß3+ neurons in SC and in the brain (cortex, white matter, hippocampus, and cerebellum). Besides, multiple cells co-expressed OPN and MTs. Granular OPN signals were detected in secretory vesicles of Golgy (αvß3 neurons) and in patches adjacent to the plasma membrane (subventricular zone). The findings imply that in demyelinating lesions are generated proteolytic OPN fragments and that OPN/MT interactions contribute to tissue remodeling during an autoimmune attack.

Hippocampal expressions of metallothionein I/II and glycoprotein 96 in EAE-prone and EAE-resistant strains of rats.

Inflammatory demyelinating diseases such as multiple sclerosis and experimental autoimmune encephalomyelitis (EAE) are often followed by cognitive deficits associated with the neuronal injury, synaptic loss and altered neurogenesis within the hippocampus. Changes depend on the genetic and epigenetic factors that ensure the cellular and environmental homeostasis and regulate the interactions of immunocompetent, glial and neural cells. Owing to high impact of stress proteins on these processes, in this study we compared the protein content of interleukin-6, transforming growth factor-ß1, metallothioneins I/II (MTs) and glycoprotein 96 (gp96) in the hippocampus of DA and AO rats that differ in the susceptibility to the induction of EAE, and tested the relationship of MTs and gp96 to granule neurons, glial cells and neural progenitors in different subfields of dentate gyrus. Rats were immunized with bovine brain homogenate emulsified in complete Freund's adjuvant or only with CFA. The data showed that acute attack of EAE in DA rats was followed by accumulation of IL-6, TGF-ß1 and MTs proteins, by increased expression of MTs in molecular and granular cell layer, by reduced expression of gp96/granular cell, by apoptosis and by microgliosis with appearance of Iba-1+ cells, co-expressing MT I/II and gp96. Furthermore, in subgranular zone (SGZ) of DA rats an augmented number of GFAP+ precursors, but decreased number of doublecortin (DCX)+ neuroblasts and immature NeuN+ neurons were found, implying that in DA rats the neurogenesis was delayed or reduced. Besides, in SGZ of both strains several DCX+ and NeuN+ cells co-expressing gp96 and MT I/II were found.

Chronic iron overload induces gender-dependent changes in iron homeostasis, lipid peroxidation and clinical course of experimental autoimmune encephalomyelitis.

To analyze iron- and gender-dependent mechanisms possibly involved in pathogenesis of multiple sclerosis (MS) in this study we evaluated the effects of iron overload (IO) on iron status and lipid peroxidation processes (LPO) in tissues of female and male DA rats during chronic relapsing experimental autoimmune encephalomyelitis, a well-established MS animal model. Rats were treated by iron sucrose (75mg/kg bw/day) or with saline solution during two weeks before the sensitization with bovine brain homogenate in complete Freund's adjuvant. Clinical signs of EAE were monitored during 29 days. Serum and tissues of CNS and liver were sampled before immunization and at day 13th post immunization (during acute phase of EAE). The determination of ferritin, iron, malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) and evaluation of histopathology were performed by ELISA, ICP spectrometry and immunohistochemistry. Results showed that IO in female EAE rats accelerated the onset of disease. In contrast, in male rats it accelerated the progression of disease and increased the mortality rate. During acute phase of EAE female IO rats sequestered more Fe in the liver, spinal cord and in the brain and produced more ferritin than male EAE rats. Male rats, however, reacted on IO by higher production of MDA or 4-HNE in the neural tissues and showed greater signs of plaque formation and gliosis in spinal cord. The data point to sexual dimorphism in mechanisms that regulate peripheral and brain iron homeostasis and imply that men and women during MS might be differentially vulnerable to exogenous iron overload.

Thymic alterations induced by partial hepatectomy: Upregulation of glycoprotein 96, CD91 and TLR2 and generation of regulatory T cells.

Glycoprotein 96 (gp96) is an endoplasmic reticulum (ER)-resident heat shock protein. It controls the folding of nascent membrane-spanning and secretory proteins, participates in stress-induced unfolded protein response (UPR) and in pathways leading to proteolysis of damaged proteins through ER-associated degradation pathways and chaperone-mediated autophagy. In addition, gp96 controls the steroid biosynthesis and Ca²âº homeostasis and participates in insulin-IGF/signaling pathways. Besides, owing to its peptide chaperone capacity and ability to interact with antigen-presenting cells, gp96 has been implicated in priming of innate and adaptive immunity. In an attempt to visualize the intensity of ER-stress in thymus and possible participation of gp96 in generation of auto-reactive T cell clones that were detected in regenerating liver, in this study we investigated the dynamics of gp96 expression in partially hepatectomized (pHx) and sham Hx mice. Simultaneously, we detected the thymic expression of receptors responsible for endocytosis of gp96-chaperoned peptides (CD91) and intracellular activation of ER-stress pathways (TLR2), as well as the expression of TGF-ß and the distribution of CD4+CD25+FoxP3+ cells. The data have shown that both pHx and sham Hx induced an accelerated apoptosis and hypoplasia in thymus. Partial Hx induced, however, a higher expression of gp96, the translocation of the CD91, TLR2 and TGF-ß immunostaining from medulla to cortex and an appearance of Treg cells. The data show that pHx triggers in thymus the ER-stress and UPR response and suggest that gp96 participates in the generation of natural Treg cells, which might be involved in the control of liver regeneration in the periphery.

Metallothioneins and trace elements dyshomeostasis induced by exposure to gasoline vapor in mice.

To investigate the effects of air pollution related with the gasoline/petrochemical industry the expression of metallothionein I (MT-I) mRNA and tissue metals were analyzed in organs of mice, exposed to gasoline (G) vapor in laboratory conditions. Control groups consisted of intact mice and of those exposed in the metabolic chamber to fresh air. The data obtained by RT-PCR and inductively coupled plasma spectrometry have shown that exposure to G vapor leads to upregulation of MT-I mRNA in organs that receive a strong respiratory and olfactory input or participate in gasoline degradation and elimination (lungs, brain, kidney and liver). Besides, in the brain and in the lungs, kidney and liver a decreased tissue content of Zn²âº or Cu²âº and Mg²âº was found (p<0.001). Some of these changes were obtained also in mice closed in the metabolic chamber, pointing to the involvement of stress-induced mechanisms in the transcriptional regulation of MTs.

Metallothionein I+II expression as an early sign of chronic relapsing experimental autoimmune encephalomyelitis in rats.

Metallothioneins (MTs) are small, cysteine-rich proteins which have been implicated in various forms of stress providing cytoprotective action against oxidative injury, DNA damage and apoptosis. Owing to their high affinity for physiological metals, such as zinc and copper MTs are also critical components of regulatory proteins involved in cell growth and multiplication, as well as in the maintenance of immune homeostasis. To elucidate the role of MTs in the pathomechanisms of autoimmune CNS disorders we estimated the expression of MT I+II proteins and the content of free Zn ions in the brain, spinal cord and in the liver early in the course of chronic relapsing experimental autoimmune encephalomyelitis (CR-EAE) pathogenesis, i.e. before the onset of any clinical symptoms. Disease was induced in the genetically susceptible Dark Agouti (DA) rats by subcutaneous injection of bovine brain homogenate in CFA. Control animals were treated with CFA alone. The data, obtained by immuno-histochemistry and in situ fluorescent labeling of free zinc ions, have shown that in the presymptomatic phase of CR-EAE (on the seventh postimmunization day) MTs I+II were markedly upregulated in the cells that form blood-brain and blood-cerebrospinal fluid barriers, as well as in the cerebellar parenchyma and hippocampal dentate gyri. Furthermore, we found that the liver also becomes a site of extensive MTs I+II synthesis shortly after immunization. Simultaneously, tissue content of free zinc ions increased at the sites of MTs induction, reflecting their antioxidative activity. The data, described in this paper point to regulatory and neuroprotective role of MTs in the pathogenesis of CR-EAE.

Endoplasmic reticulum resident heat shock protein-gp96 as morphogenetic and immunoregulatory factor in syngeneic pregnancy.

The severe remodeling of endometrial stroma during blastocyst adhesion and trophoblast invasion initiates at maternal-fetal interface the reaction of evolutionary old heat shock response, in which heat shock proteins, as molecular chaperons, monitor the configurations of newly synthesized proteins and prevent the formation of functionless aggregates of misfolded proteins, targeting them to degradation by a the ubiquitin-proteasome system. In addition, the endoplasmic reticulum (ER)-resident HSPs, such as gp96/GRP94 may, after binding to CD91 and TLRs, elicit antigen-specific and antigen-unspecific immune responses, owing to its peptide-chaperoning capacity and ability to activate APCs. Considering these properties, we examined tissue expression of gp96 at the maternal-fetal interface and in the maternal liver and spleen on the 16th day of undisturbed syngeneic pregnancy and after the treatment with peptidoglycan monomer linked with zinc (PGM-Zn). The data showed that in undisturbed pregnancy the gp96, CD91 and TLR2 were markedly expressed on extravillous and villous trophoblast. PGM-Zn enhanced these findings, as well as the number of uterine natural killer cells and local NFκB immunoreactivity. Gp96 expression arose also in the maternal spleen and liver, where an accumulation of NKT cells or γδT lymphocytes was seen. The data point to roles of gp96 in maintenance of proteostasis and local and systemic immune balance in pregnancy complicated by infection.

Metallothioneins I/II expression in rat strains with genetically different susceptibility to experimental autoimmune encephalomyelitis.

OBJECTIVES: Compared to the Dark Agouti (DA), the Albino Oxford (AO) rat strain exhibits lower susceptibility to the induction of experimental autoimmune encephalomyelitis (EAE). Here, we investigated the potential contribution of the heavy metal-binding proteins metallothioneins (MTs) I/II to these effects. METHODS: Rats were immunized with bovine brain homogenate emulsified in complete Freund's adjuvant or only with complete Freund's adjuvant. The expression patterns of MTs mRNA and proteins and tissue concentrations of Zn2+ and Cu2+ were estimated in the brain and in the liver on days 7 and 12 after immunization, by real-time PCR, immunohistochemistry and inductively coupled plasma spectrometry, respectively. Additionally, the hepatic transforming growth factor beta and nuclear factor kappa B immunoreactivities were tested. RESULTS: Clinical signs of EAE were not induced in AO rats, but they upregulated the expression of MT I/II proteins in the brain (hippocampus and cerebellum) and in the liver, similarly as DA rats. The transcriptional activation of MT-I occurred, however, only in DA rats, which accumulated also more zinc in the brain and in the liver. In contrast, intact AO rats had greater hepatic MT-I mRNA immunoreactivity and more Cu2+ in the hippocampus. Besides, in immunized AO rats a high upregulation of transforming growth factor beta and nuclear factor kappa B immunoreactivities was found in several hepatic structures (vascular endothelium, Kupffer cells and hepatocytes). CONCLUSIONS: Our data show that AO and DA rats differ in constitutive and inductive MT-I gene expression in the brain and in the liver, as well as in the hepatic cytokine profile, suggesting that these mechanisms may contribute to the discrepancy in the susceptibility to EAE.

Hepatic expression of metallothionein I/II, glycoprotein 96, IL-6, and TGF- ß in rat strains with different susceptibilities to experimental autoimmune encephalomyelitis.

In a search of peripheral factors that could be responsible for the discrepancy in susceptibility to EAE in Albino Oxford (AO) and Dark Agouti (DA) rats, we estimated the expression of metallothioneins I/II (MT), heat shock protein-gp96, interleukin (IL)-6, and transforming growth factor (TGF)- ß in the livers of these animals. Rats were immunized with bovine brain homogenate (BBH) emulsified in complete Freund adjuvant (CFA) or only with CFA. Western blot and immunohistochemical analyses were done on day 12 after the immunization, as well as in intact rats. The data have shown that during the first attack of EAE only the EAE prone-DA rats markedly upregulated the hepatic MTs, gp96, IL-6, and TGF- ß . In contrast, AO rats had a significantly higher expression of MT I/II, IL-6, and TGF- ß in intact liver (P < 0,001), suggesting that the greater constitutive expression of these proteins contributed to the resistance of EAE. Besides, since previously we found that AO rats reacted on immunization by an early upregulation of TGF- ß on several hepatic structures (vascular endothelium, Kupffer cells, and hepatocytes), the data suggest that the specific hepatic microenvironment might contribute also to the faster recovery of these rats from EAE.

Heat shock protein Gp96 as potential regulator of morphostasis after partial hepatectomy in mice.

Gp96 (also known as glucose-regulated protein 94, endoplasmin) is the endoplasmic reticulum (ER)-resident protein, which belongs to the heat shock protein HSP90 family. It is upregulated in response to glucose starvation and other stressful stimuli that disrupt protein synthesis in the ER. There, it is acting as a molecular chaperon involved in the correction of unfolded proteins, in the activation of proteasome-dependent ER-associated degradation of the misfolded proteins, and in activation of protein translations that modulate the polypeptide traffic into the ER. In addition, it has been implicated in antigen presentation and MHC class I and II upregulation, in the activation and maturation of dendritic cells and proinflammatory cytokine secretion, as well as in chaperoning of integrins and Toll-like receptors, acting as a "danger signal" to the innate and adaptive immunity. Moreover, owing to its specific function in Ca2+ homeostasis and in the insulin- IGF/signaling pathways, it has been proposed that gp96 might participate in mechanisms that are critical for cell growth, differentiation, and responses to ER stress. Emphasizing that gp96, as a natural adjuvant for chaperoning antigenic self peptides into the immune surveillance pathways, may also be involved in the maintenance of morphostasis and self tolerance, in this survey we show that high levels of upregulation of gp96 in regenerating liver and thymus are followed by signs of transient autoimmunity, augmented apoptosis in thymus, and the presence of autoreactive NKT and regulatory T cells that might be involved in the control of rapid liver growth induced by partial hepatectomy.

Kinetics of tissue iron in experimental autoimmune encephalomyelitis in rats.

To elucidate the role of iron in the pathomechanisms of autoimmune CNS disorders, we estimated the tissue concentrations of Fe(2+) in the brain, spinal cord, and liver in the chronic relapsing form of experimental autoimmune encephalomyelitis (EAE). The disease was induced in Dark Agouti (DA) strain of rats, by subcutaneous injection of bovine brain homogenate in complete Freund's adjuvant (CFA). Control rats consisted of unsensitized rats and of rats treated with CFA or saline. The data obtained by clinical assessment and by inductively coupled plasma spectrometry have shown that the attacks of disease (on the 12th and 22nd post-immunization day) were followed by high accumulation of iron in the liver. Additionally, during the second attack of disease, the decreased concentration of Fe(2+) was found in cervical spinal cord. The data point to regulatory effects of iron and hepatic trace elements regulating mechanisms in the pathogenesis of EAE.

Time-course expression of metallothioneins and tissue metals in chronic relapsing form of experimental autoimmune encephalomyelitis.

To elucidate the role of metallothioneins (MTs) in the pathomechanisms of autoimmune CNS disorders we estimated the expression of MTs I+II and the tissue concentrations of Zn²+ and Cu²+ in the brain, spinal cord (SC) and in the liver during the periods of attacks and remissions in chronic relapsing experimental autoimmune encephalomyelitis (CR-EAE). Disease was induced in the genetically susceptible Dark Agouti (DA) rats by subcutaneous injection of bovine brain homogenate in CFA. Control rats were treated with CFA. The data, obtained by clinical assessment, immunohistochemistry and inductivity coupled plasma spectrometry, have shown that during the first attack (on the 12th day) MTs I+II were markedly upregulated in subarachnoid regions and perivascular space on astrocytes, microglia and on spinal neurons. Simultaneously, the concentrations of zinc in the SC and zinc and copper in the liver have found to be increased. During the second attack (on the 22nd day) a new overexpression of MTs was found in the cerebellum, in sulcus hippocampi, in spinal neurons and particularly in hepatocytes around the central vein. Concomitantly, in the brain and SC the concentration of copper increased. The data point to a neuroprotective role of MTs and to an important regulatory role of essential metals and hepatic MTs in the pathogenesis of CR-EAE.

Perforin expression in peripheral blood lymphatic cells of patients subjected to laparoscopic or open cholecystectomy.

Perforin-(P-) related characteristics of cytotoxic T lymphocytes and natural killer cells were investigated in peripheral blood of patients subjected to open (OC; n = 23) or laparoscopic cholecystectomy (LC; n = 21) and healthy controls (n = 20). Blood samples were obtained preoperatively and 24 hours after the surgeries, and the data were correlated with the intensity of cholestasis and concomitant inflammation, determined by functional hepatic tests. Postoperative differences were found to be minimal: OC decreased only the percentage of CD56(+) cells, while LC decreased the fraction of CD8(+)P(+) cells and augmented the mean fluorescence intensity of P in CD56 cells. Patients elected for OC had, however, higher preoperative numbers of total P(+), CD3(+)P(+), and CD4(+)P(+) cells than patients elected for LC and healthy controls, while both groups of patients, preoperatively, had lower fraction of CD16(+)P(+) and CD56(+)P(+) cells. These changes were in high correlation with blood concentrations of CRP, AP, and ALT, emphasizing the link between the preoperative cholestasis and inflammation and P-dependent cytotoxic mechanisms.

Dose- and time-dependent effects of luteolin on carbon tetrachloride-induced hepatotoxicity in mice.

Carbon tetrachloride (CCl(4)) is a well-known model compound for producing chemical hepatic injury. This study investigated the protective effects of the flavonoid luteolin on the CCl(4)-induced hepatotoxicity in mice. Luteolin dissolved in dimethyl sulfoxide (DMSO) was administered intraperitoneally (i.p.) at 5 or 50 mg/kg as a single dose, and once daily for 2 consecutive days. Two hours after the final treatment, the mice were treated with CCl(4) (20 mg/kg, i.p.). CCl(4)-induced hepatotoxicity was reduced in a dose- and time-dependent manner, as determined by decreased serum aminotransferase activities and liver histopathology. CCl(4) intoxication resulted in an overexpression of heat shock protein gp96 in the mice liver, which was strongly attenuated by luteolin pretreatment. Luteolin has also decreased oxidative stress produced by CCl(4), as suggested by improvement in the Cu/Zn superoxide dismutase activity. The effect of luteolin on myeloperoxidase, an indicator of inflammatory cell infiltration, was also investigated. Treatment of the mice with luteolin resulted in a significant decrease in the myeloperoxidase activity. The hepatoprotective effect of luteolin against CCl(4) hepatotoxicity was higher in animals pretreated with luteolin for 2 consecutive days. This suggests that the protection might be due to induction of some adaptive mechanisms. The data indicate that luteolin could be effective in protecting mice from the hepatotoxicity produced by CCl(4).

Metallothioneins and heat shock proteins 70 in marine mussels as sensors of environmental pollution in Northern Adriatic Sea.

In an attempt to assess the intensity of environmental pollution in industrial zones of Kvarnerian Bay in Northern Adriatic Sea and the reactivity of Mytilus galloprovincialis to these changes, in this study we estimated the concentration of heavy metals at four locations in both sea-sediment and in the mussels. Further we tried to correlate these changes with seasonal variations in environmental temperature, pH and salinity, as well as with the expression of metallothioneins (MTs) and heat shock proteins (HSPs) in the digestive tract of the mussels. Sampling in vivo was performed monthly, during the year 2008, while under the laboratory conditions the reactivity of acclimated mussels were tested to increasing concentrations of CdCl(2) and to thermal stress. The data have shown that the induction of MTs and HSP isoforms of the 70-kDa size class were highly affected by model agents treatment including contamination of sea-sediment by Pb, Hg and Cd, implying that these stress proteins might be power biomarkers of marine pollution.

Dose- and time-dependent effects of luteolin on liver metallothioneins and metals in carbon tetrachloride-induced hepatotoxicity in mice.

The aim of this study was to investigate the protective effect of luteolin on liver Ca, Mg, Zn, Cu, Fe, and Mn content in mice with carbon tetrachloride (CCl4)-induced hepatotoxicity. Additionally, liver metallothionein (MT) expression was studied. Luteolin was administered intraperitoneally (i.p.) as a single 5- or 50-mg/kg dose or once daily for two consecutive days, respectively. Two hours after the last injection, the mice were treated with CCl4 (20 mg/kg, i.p.). CCl4 injection reduced hepatic level of all metals except Ca, with an intense cytoplasmic staining pattern in hepatocytes located in periportal areas, indicating induction of MTs. Pretreatment with 50 mg/kg of luteolin for 2 days remarkably elevated metal content to control values (Mg and Cu) or even above them (Zn and Fe). Luteolin pretreatment increased pericentral MTs immunopositivity and histological architecture improvement in a time- and dose-dependent manner, being the most prominent in mice pretreated with 50 mg/kg for 2 days. The liver in this group showed pronounced MT expression in almost all hepatocytes throughout the liver parenchyma. In conclusion, these results suggest the protective effect of luteolin on CCl4-induced hepatotoxicity and an enhancement of hepatocyte proliferative capabilities.

Heat shock protein-GP96 as an innate sensor of damage and activator of autoreactive NKT and regulatory T cells during liver regeneration.

Tissue disintegration after injury leads, in the endoplasmic reticulum (ER), to activation of adaptive pathways known as the ER stress response. It is directed to the correction of unfolded proteins and to the activation of proteasome-dependent ER-associated degradation of the misfolded proteins, but induces also a rapid activation of natural and adaptive immunity, since a ER resident heat shock protein-gp96 acts not only as a molecular chaperone, but also as a strong adjuvant, able to cross-present the antigenic peptides onto MHC class I or MHC class II pathways. Analyzing its potential role in processes of normal growth, in mice subjected to 1/3 partial hepatectomy (pHx) we determined the tissue expression of gp96 protein and mRNA in regenerating liver, thymus and spleen, determining simultaneously the phenotypic profile and spontaneous cytotoxic activity of intrahepatic and splenic mononuclear lymphatic cells (MNLC) against NKT- and NK-cells sensitive targets (syngeneic thymocytes and YAC-1) in wild, perforin and FasL deficient mice. The data have shown that pHx induces fast overexpression of gp96 protein and mRNA in hepatocytes, spleen and thymus, with accumulation of CD3intermediate/NK1.1+/CD69+ cells (liver) and Foxp3+CD4+CD25+ cells (liver and thymus). Simultaneously, intrahepatic MNLC acquired the FasL-dependent cytotoxic potential against NKT-sensitive targets and both, intrahepatic and splenic MNLC, acquired the perforin-dependent cytotoxic potential against NK-sensitive targets, implying that during the disturbance of morphostasis gp96 serves as a natural adjuvant for chaperoning antigenic self peptides into the immune surveillance pathways, resulting in activation of autoreactive NKT and regulatory cells, as well as NK cells. Moreover, cell cycle analysis revealed that G2+M phase of regenerating hepatocytes in PKO mice was translocated from the 1st to the 7th p. o. day, as well as that hepatocytes from FasL deficient mice were arrested in G0/G1 phase.